Inter-Satellite Links (ISLs) are intended to improve precision of orbit determination and satellite clock estimation. The ISLs provide a precise pseudorange measurements between satellites in a specific constellation. The study is a preparatory assessment of exploitation of seven connectivity schemes in the terms of the precise orbit determination for three types of constellations—Galileo-like with 24 satellites on three orbital planes, GPS-like with 24 satellites on six orbital planes, and GPS with real positions. The first part of the study focused on detailed analysis of the various ISL connectivity schemes, considering the geometry of ISL observations. The selected results of ranging were examined in the context of the precise orbit determination based on weighted least squares adjustment. The second part of the analysis was based on simulated measurements with two approaches. First approach focuses on geometrical dependencies and the second is performed with ISL measurement biases estimation. It was found that the use of the ISL technique with GNSS measurements in orbit determination improves the results by reducing the RMS error in the along-track and cross-track components. Choice of connectivity schemes does not have a significant impact on the total results of orbit determination, but give different contribution to particular components. Introducing constant bias in ISL measurements occurs in slightly worse estimation results. However, the relations between connectivity schemes is very similar to approach without simulation of ISL bias, the differences are at the level of 10%. Satellite and station clock estimation errors are almost equal for all used connectivity schemes. Results of clocks are also not influenced by ISL bias. This study showed that the ISL technique is a highly promising addition for future generations of satellite navigation systems and that sequential and ring connectivity schemes can be recommended for use in future navigation constellations.

卫星间链路（ISL）旨在提高轨道确定和卫星时钟估计的精度。ISL在特定星座中的卫星之间提供精确的伪距测量。这项研究是对三种类型的星座的精确轨道确定方面的七种连通性方案开发的准备性评估：类似于伽利略的3轨道平面上有24颗卫星，类似于GPS的6轨道平面上有24颗卫星和GPS有实际职位。研究的第一部分着重于对各种ISL连接方案的详细分析，同时考虑了ISL观测的几何形状。在基于加权最小二乘平差的精确轨道确定的背景下，检查了测距的选定结果。分析的第二部分基于两种方法的模拟测量。第一种方法侧重于几何相关性，第二种方法是使用ISL测量偏差估计进行的。发现在轨道确定中将ISL技术与GNSS测量结合使用，可以减少沿航迹和跨航迹分量的RMS误差，从而改善结果。连通性方案的选择不会对确定轨道的总体结果产生重大影响，但会对特定组件做出不同的贡献。在ISL测量中引入恒定偏差会产生稍差的估计结果。但是，连通性方案之间的关系与没有模拟ISL偏差的方法非常相似，差异在10％的水平上。对于所有使用的连接方案，卫星和站时钟估计误差几乎相等。时钟的结果也不受ISL偏差的影响。这项研究表明，ISL技术是下一代卫星导航系统的极有希望的补充，并且可以推荐将顺序连接和环形连接方案用于未来的导航星座。